Time-domain iq mismatch compensator with frequency-domain observations

ABSTRACT

A system, method, and electronic device for compensating in-phase (I) and quadrature (Q) mismatch (IQMM) are herein disclosed. The system includes an IQ mismatch compensator (IQMC) configured to compensate for IQMM between a time-domain I signal and a time-domain Q signal using filter weight coefficients, and output a compensated I signal and a compensated Q signal, a fast Fourier transformation (FFT) circuit configured to perform an FFT on the compensated I signal and the compensated Q signal to a frequency-domain compensated signal, and a coefficient updater configured to update the filter weight coefficients based on a frequency-domain observation of the frequency-domain compensated signal.

PRIORITY

This application is based on and claims priority under 35 U.S.C. §119(e) to a U.S. Provisional patent application filed on Sep. 26, 2018in the United States Patent and Trademark Office and assigned Ser. No.62/736,595, the entire contents of which are incorporated herein byreference.

FIELD

The present disclosure relates generally to a method and system formismatch compensation between in-phase and quadrature branches indown-conversion receivers. In particular, the present disclosure relatesto a time-domain IQ mismatch compensator with frequency-domainobservations.

BACKGROUND

The imbalance between in-phase (I) and quadrature (Q) branches ofdown-conversion receivers creates interference between the mirrorfrequencies after down-conversion to the baseband. The IQ mismatch(IQMM) caused by non-ideal characteristics of I and Q paths degrades thesystem performance by reducing the effective signal to interferenceratio. Hence, IQ mismatch compensation (IQMC) is crucial for the designof wideband systems with quadrature down-conversion architecture.

SUMMARY

According to one embodiment, system for compensating IQMM is provided.The system includes an IQ mismatch compensator (IQMC) configured tocompensate for IQMM between a time-domain I signal and a time-domain Qsignal using filter weight coefficients, and output a compensated Isignal and a compensated Q signal, a fast Fourier transformation (FFT)circuit configured to perform an FFT on the compensated I signal and thecompensated Q signal to a frequency-domain compensated signal, and acoefficient updater configured to update the filter weight coefficientsbased on a frequency-domain observation of the frequency-domaincompensated signal

According to one embodiment, a method for compensating IQMM is provided.The method includes compensating, with an IQMC, for IQMM between atime-domain I signal and a time-domain Q signal using filter weightcoefficients, outputting, with the IQMC, a compensated I signal and acompensated Q signal, transforming, with an FFT circuit, the compensatedI signal and the compensated Q signal to a frequency-domain compensatedsignal, and updating, with a coefficient updater, the filter weightcoefficients based on a frequency-domain observation of thefrequency-domain compensated signal

According to one embodiment, an electronic device for compensating IQMMis provided. The electronic device includes an IQMC, an FFT circuit, acoefficient updater, a processor, and a non-transitory computer readablestorage medium storing instructions that, when executed, cause theprocessor to compensate, with the IQMC, for IQMM between a time-domain Isignal and a time-domain Q signal using filter weight coefficients,output, with the IQMC, a compensated I signal and a compensated Qsignal, transform, with the FFT circuit, the compensated I signal andthe compensated Q signal to a frequency-domain compensated signal, andupdate, with the coefficient updater, the filter weight coefficientsbased on a frequency-domain observation of the frequency-domaincompensated signal.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the present disclosure will be more apparent from thefollowing detailed description, taken in conjunction with theaccompanying drawings, in which:

FIG. 1 is a diagram of a system 100 for compensating for IQMM, accordingto an embodiment;

FIG. 2 is a flowchart of a method for compensating for IQMM, accordingto an embodiment;

FIG. 3 is a diagram of an IQMC, according to an embodiment;

FIG. 4 is a diagram of a system for IQMM compensation and filter weightcoefficient updating in an iterative kurtosis-based adaptation,according to an embodiment;

FIG. 5 is a diagram of a system for IQMM compensation and filter weightcoefficient updating in an iterative Euclidean distance (ED)-basedadaptation, according to an embodiment; and

FIG. 6 is a block diagram of an electronic device in a networkenvironment, according to one embodiment.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure are described indetail with reference to the accompanying drawings. It should be notedthat the same elements will be designated by the same reference numeralsalthough they are shown in different drawings. In the followingdescription, specific details such as detailed configurations andcomponents are merely provided to assist with the overall understandingof the embodiments of the present disclosure. Therefore, it should beapparent to those skilled in the art that various changes andmodifications of the embodiments described herein may be made withoutdeparting from the scope of the present disclosure. In addition,descriptions of well-known functions and constructions are omitted forclarity and conciseness. The terms described below are terms defined inconsideration of the functions in the present disclosure, and may bedifferent according to users, intentions of the users, or customs.Therefore, the definitions of the terms should be determined based onthe contents throughout this specification.

The present disclosure may have various modifications and variousembodiments, among which embodiments are described below in detail withreference to the accompanying drawings. However, it should be understoodthat the present disclosure is not limited to the embodiments, butincludes all modifications, equivalents, and alternatives within thescope of the present disclosure.

Although the terms including an ordinal number such as first, second,etc. may be used for describing various elements, the structuralelements are not restricted by the terms. The terms are only used todistinguish one element from another element. For example, withoutdeparting from the scope of the present disclosure, a first structuralelement may be referred to as a second structural element. Similarly,the second structural element may also be referred to as the firststructural element. As used herein, the term “and/or” includes any andall combinations of one or more associated items.

The terms used herein are merely used to describe various embodiments ofthe present disclosure but are not intended to limit the presentdisclosure. Singular forms are intended to include plural forms unlessthe context clearly indicates otherwise. In the present disclosure, itshould be understood that the terms “include” or “have” indicateexistence of a feature, a number, a step, an operation, a structuralelement, parts, or a combination thereof, and do not exclude theexistence or probability of the addition of one or more other features,numerals, steps, operations, structural elements, parts, or combinationsthereof.

Unless defined differently, all terms used herein have the same meaningsas those understood by a person skilled in the art to which the presentdisclosure belongs. Terms such as those defined in a generally useddictionary are to be interpreted to have the same meanings as thecontextual meanings in the relevant field of art, and are not to beinterpreted to have ideal or excessively formal meanings unless clearlydefined in the present disclosure.

The electronic device according to one embodiment may be one of varioustypes of electronic devices. The electronic devices may include, forexample, a portable communication device (e.g., a smart phone), acomputer, a portable multimedia device, a portable medical device, acamera, a wearable device, or a home appliance. According to oneembodiment of the disclosure, an electronic device is not limited tothose described above.

The terms used in the present disclosure are not intended to limit thepresent disclosure but are intended to include various changes,equivalents, or replacements for a corresponding embodiment. With regardto the descriptions of the accompanying drawings, similar referencenumerals may be used to refer to similar or related elements. A singularform of a noun corresponding to an item may include one or more of thethings, unless the relevant context clearly indicates otherwise. As usedherein, each of such phrases as “A or B,” “at least one of A and B,” “atleast one of A or B,” “A, B, or C,” “at least one of A, B, and C,” and“at least one of A, B, or C,” may include all possible combinations ofthe items enumerated together in a corresponding one of the phrases. Asused herein, terms such as “1^(st)”, “2nd,” “first,” and “second” may beused to distinguish a corresponding component from another component,but are not intended to limit the components in other aspects (e.g.,importance or order). It is intended that if an element (e.g., a firstelement) is referred to, with or without the term “operatively” or“communicatively”, as “coupled with,”, to, ““connected with coupled”” or“connected to” another element (e.g., a second element), it indicatesthat the element may be coupled with the other element directly (e.g.,wiredly), wirelessly, or via a third element.

As used herein, the term “module” may include a unit implemented inhardware, software, or firmware, and may interchangeably be used withother terms, for example, “logic,” “logic block,” “part,” and“circuitry.” A module may be a single integral component, or a minimumunit or part thereof, adapted to perform one or more functions. Forexample, according to one embodiment, a module may be implemented in aform of an application-specific integrated circuit (ASIC).

The systems, methods, and devices provided herein adapt time-domain IQMCfilter weights in quadrature down-conversion receivers usingfrequency-domain observations to compensate frequency-independent IQMM(FI-IQMM) and frequency-dependent IQMM (FD-IQMM). In particular, thesystems, methods, and devices use frequency-domain observations to adaptfilter coefficients in a real-valued time-domain IQMC according to oneembodiment. Domain observations may be referred to interchangeably asdomain signals. A gradient of a generic frequency-domain cost function(such as kurtosis and ED cost functions) with respect to thecoefficients of a real-valued time-domain IQMC is obtained that dependsonly on the filter coefficients and frequency-domain observations.

A gradient descent approach is utilized to adjust the filter weights ateach iteration. However, any other method can be used to adapt thefilter weights. Other methods such as a Newton algorithm can also beused to adjust the filter weights. However, this method requiresobtaining the Hessian matrix which is the second-order partialderivative of the cost function with respect to IQMC filtercoefficients. The gradient of a generic frequency-domain cost functionwith respect to filter coefficients generally depends on the time-domainobservations. This gradient is obtained for a generic cost function suchthat it only depends on the frequency-domain observations and filterweights rather than the time-domain observations. Two different costfunctions are utilized for IQMC compensation in orthogonalfrequency-division multiplexing (OFDM) systems that result in twosemi-blind algorithms, the first being kurtosis of the frequency-domainobservation and the second being Euclidean distance (ED) between thefrequency-domain impaired signal and the received constellation.

FIG. 1 is a diagram of a system 100 for compensating for IQMM, accordingto an embodiment. The system 100 includes an IQMC 102, a fast Fouriertransformation (FFT) circuit 104, and a filter weight coefficientupdater 106.

A signal 108 is input to the system 100. The signal 108 is sent throughan I path down conversion 110 and Q path down conversion 112 and atime-domain I observation 114 and a time-domain Q observation 116 areobtained, respectively. The observations 114 and 116 are sent to theIQMC 102 for compensation. Utilizing filter weight coefficients, theIQMC 102 generates a compensated I signal 118 and a compensated Q signal120. The compensated signals 118 and 120 are sent to the FFT 104 totransform the signals into the frequency-domain. The frequency-domainsignal 122 may be output from the system 100. Furthermore, afrequency-domain observation 124 is obtained from the signal 122. Thefrequency-domain observation 124 is sent to the coefficient updater 106and is used to update the filter weight coefficients as will bedescribed in detail further below.

FIG. 2 is a flowchart 200 of a method for compensating for IQMM,according to an embodiment. At 202, IQMM between a time-domain I signaland a time-domain Q signal is compensated. The IQMM may be compensatedby an IQMC.

FIG. 3 is a diagram of a real-valued IQMC 300, according to anembodiment. The time-domain I observation 302 is fed into delay element306 and the IQMC 300 generates a compensated I signal 308. Thetime-domain Q observation 304 is fed through a filter with weightcoefficients w[n] 310. The signal output from 306 is combined with asecond filter weight coefficient (a) 312 through mixer 314. The signaloutput from 310 is then added with the mixed signal at 314 via adder316, and the signal generated is the compensated Q signal 318. Thus, theIQMC 300 generates compensated signals 308 and 318 using filter weightcoefficients 310 and 312.

Referring back to flowchart 200 of FIG. 2, at 204, the compensated Isignal and compensated Q signal are outputted. The IQMC 300 may outputthe generated and compensated I signal 308 and Q signal 318.

At 206, the output compensated signals are transformed to thefrequency-domain. The transformation may be performed by an FFT circuit.The signals when compensated by the IQMC 300 are compensated in thetime-domain, requiring a transformation to the frequency-domain forfurther functionality.

At 208, the filter weight coefficients are updated based on afrequency-domain observation of the transformed signals. The filterweight coefficients may be updated by a coefficient updater, as isdescribed in further detail below.

One purpose of the systems, methods, and devices disclosed herein is toupdate filter weights α∈

and w=[w[0], . . . w[L−1]]^(T)∈

^(L×1) of a real-valued time-domain IQMC to compensate IQMM. Thesefilter coefficients are updated based on the frequency domainobservations Y_(k), k=−K, . . . , +K, where k is the index of thesubcarrier. As shown herein, the IQMC is located in the time-domain.

Given x=[α w^(T)]^(T) as the filter coefficients of real-value IQMC. Thefilter weight coefficients are updated at the (l+1)th iteration usinggradient descent algorithm as in Equation (1):

$\begin{matrix}{{{x^{l + 1} = \left. {x^{l} - {\frac{\mu}{2K}{\sum\limits_{k = {- K}}^{K}\frac{\partial J_{k}}{\partial x}}}} \right|_{x = x^{l}}},}\;} & (1)\end{matrix}$

where J_(k)=f(Y_(k)) is the cost function at the kth subcarrier, whichis a function of frequency-domain observations, and μ is step size,which can be a function of iteration. From Equation (1) it can be seenthat the gradient of cost function J_(k) with respect to filtercoefficients, i.e.,

$\frac{\partial J_{k}}{\partial x}$

needs to be calculated. This gradient, in general, depends on the timedomain observations z[n] (z[n]=z_(I)[n]+jz_(Q)[n]), which in turn,requires a time domain buffer to store z[n]. However, as is describedherein, the gradient of cost function is obtained as a function of α,frequency response of w (i.e., W_(k)) and frequency-domain observationsY_(k), k=−K, . . . , +K.

In one example, kurtosis of Y_(k) is utilized as the cost function.Kurtosis of the k-th tone observations Y_(k) is defined as in Equation(2):

$\begin{matrix}{{{{kurt}(k)} = \frac{M{\sum\limits_{t = 1}^{M}\; {Y_{k}^{(t)}}^{4}}}{\left( {\sum\limits_{t = 1}^{M}\; {Y_{k}^{(t)}}^{2}} \right)^{2}}},} & (2)\end{matrix}$

where superscript (τ) is the OFDM symbol index and M is the number ofOFDM symbols for which the kurtosis is computed.

In another example, ED between the post-FFT impaired signal and thereceived constellation is utilized as our cost function which is givenby Equation (3):

$\begin{matrix}{{{{ED}(k)} = {\frac{1}{M}{\sum\limits_{t = 1}^{M}\; {{Y_{k}^{(t)} - {U_{1,k}H_{k}^{(t)}X_{k}^{(t)}}}}^{2}}}},} & (3)\end{matrix}$

where U_(1,k)H_(k) ^((t))X_(k) ^((t)) is referred to as theconstellation, X_(k) ^((t)) is a known reference signal sent by thetransmitter, H_(k) ^((t)) is the channel response on the (t)th OFDMsymbol of the kth subcarrier, and U_(1,k) is a parameter that containseffects of IQMM and real-valued IQMC. U_(1k)H_(k) ^((t)) is knownthrough channel estimation.

The gradient of the cost function J_(k) can be computed as in Equation(4):

$\begin{matrix}{{\frac{\partial J_{k}}{\partial x_{l}} = {\sum\limits_{t = 1}^{M}\; {{Re}\left( {F_{k}^{{(t)}*}V_{k,l}^{(t)}} \right)}}},{{{for}\mspace{14mu} l} = 0},{\ldots \mspace{14mu} {L.}}} & (4)\end{matrix}$

The gradient calculation involves computing

$F_{k}^{(t)} = {{\frac{\partial J_{k}}{{\partial{Re}}\left\{ Y_{k}^{(t)} \right\}} + {j\frac{\partial J_{k}}{{\partial{Im}}\left\{ Y_{k}^{(t)} \right\}}\mspace{14mu} {and}\mspace{14mu} V_{k,l}^{(t)}}} = {\frac{{\partial{Re}}\left\{ Y_{k}^{(t)} \right\}}{\partial x_{l}} + {j\frac{{\partial{Im}}\left\{ Y_{k}^{(t)} \right\}}{\partial x_{l}}}}}$

for k=−K, . . . , K and l=0, . . . L. F_(k) ^((t)) for kurtosis-basedadaptation can be computed as in Equation (5):

$\begin{matrix}{{F_{k}^{(t)} = {{\frac{4M}{G_{2,k}}\left\lbrack {\frac{{Y_{k}^{(t)}}^{2}}{G_{2,k}} - \frac{G_{4,k}}{G_{2,k}^{2}}} \right\rbrack}Y_{k}^{(t)}}},} & (5)\end{matrix}$

where intermediate terms G_(2,k) and G_(4,k) are defined as in Equation(6):

$\begin{matrix}{{G_{2,k} = {\sum\limits_{t = 1}^{M}\; {Y_{k}^{(t)}}^{2}}},{G_{4,k} = {\sum\limits_{t = 1}^{M}\; {{Y_{k}^{(t)}}^{4}.}}}} & (6)\end{matrix}$

For ED-based adaptation, F_(k) ^((t)) can be computed as in Equation(7):

$\begin{matrix}{F_{k}^{(t)} = {\frac{2}{M}{\left( {Y_{k}^{(t)} - {U_{1,k}H_{k}^{(t)}X_{k}^{(t)}}} \right).}}} & (7)\end{matrix}$

The length of the channel plus L−2 is smaller than the cyclic prefixlength and the gradient V_(k,l) ^((t)) of the cost function with respectto the filter weight coefficients is obtained as in Equation (8):

$\begin{matrix}{V_{k,l}^{(t)} = \left\{ {\begin{matrix}{\frac{e^{\frac{j\; \pi}{2}}}{2}\left( {Y_{k}^{(t)} + Y_{- k}^{{(t)}*}} \right)} & {{{for}\mspace{14mu} l} = 0} \\{{- \frac{e^{j{({\frac{\pi}{2} - \frac{2{\pi {({l - 1})}}k}{N}})}}}{2W_{k}}}\left( {{\left( {\alpha + j} \right)Y_{k}^{(t)}} + {\left( {\alpha - j} \right)Y_{- k}^{{(t)}*}}} \right)} & {{{{for}\mspace{14mu} l} = 1},\ldots \mspace{20mu},L}\end{matrix},} \right.} & (8)\end{matrix}$

where W_(k) is the frequency-domain response of filter w[n] at the kthtone. The computation of V_(k,l) ^((t)) is the same for anyfrequency-domain cost function in the real-valued IQMC and the onlydifference between different cost functions is computation of F_(k)^((t)). If another IQMC method is used, V_(k,l) ^((t)) also changes buta similar method can be used to obtain the gradient as a function offrequency domain observations and filter weights only. The gradientdepends only on the filter coefficients and frequency-domainobservations.

FIG. 4 is a diagram of a system 400 for IQMM compensation and filterweight coefficient updating in an iterative kurtosis-based adaptation,according to an embodiment. The system 400 includes an IQMC 402, an FFTcircuit 404 and a filter weight coefficient updater 406. V_(k,l) ^((t))computation 408 is performed as in Equation (8), based onfrequency-domain observations Y_(k) ^((t)) and Y_(−k) ^((t)) at theinitial iteration (e.g., l=0, α=0 and w=[0_(1×T) _(D) , 1, 0_(1×(L-T)_(D) ₋₁₎]^(T)), and in further iterations, V_(k,l) ^((t)) computation408 is performed based on the frequency-domain response W_(k) of filterweight coefficient w[n], and filter weight coefficient α. F_(k) ^((t))scale computation 410 is performed as in Equation (5) based onintermediate terms G_(2,k) and G_(4,k), and the frequency-domainobservation parameter |Y_(k) ^((t))|².

The gradient of the cost function 412 is performed based on F_(k) ^((t))and V_(k,l) ^((t)), and the filter weight coefficients 414 are updated.The updated filter weight coefficients 414 are then sent back to theIQMC 402 for further IQMM compensation.

FIG. 5 is a diagram of a system 500 for IQMM compensation and filterweight coefficient updating in an iterative ED-based adaptation,according to an embodiment. The system 500 includes an IQMC 502, an FFTcircuit 504, and a filter weight coefficient updater 506.

V_(k,l) ^((t)) computation 508 is performed as in Equation (8), based onfrequency-domain observations Y_(k) ^((t)) and Y_(−k) ^((t))* at theinitial iteration (e.g., l=0), and in further iterations, V_(k,l) ^((t))computation 408 is performed based on the frequency-domain responseW_(k) of filter weight coefficient w[n], and filter weight coefficientα. F_(k) ^((t)) computation 510 is performed as in Equation (7), basedon frequency-domain observations Y_(k) ^((t)), a reference signal 512X_(k) ^((t)), the channel response H_(k) ^((t)) on the (t)th OFDM symbolof the kth subcarrier, and the parameter U_(1,k) that contains effectsof IQMM and real-valued IQMC, with U_(1,k)H_(k) ^((t)) being determinedfrom channel estimation 514.

The gradient of the cost function 516 is performed based on F_(k) ^((k))and V_(k,l) ^((t)), and the filter weight coefficients 518 are updated.The updated filter weight coefficients 518 are then sent back to theIQMC 502 for further IQMM compensation.

FIG. 6 is a block diagram of an electronic device 601 in a networkenvironment 600, according to one embodiment. Referring to FIG. 6, theelectronic device 601 in the network environment 600 may communicatewith an electronic device 602 via a first network 698 (e.g., ashort-range wireless communication network), or an electronic device 604or a server 608 via a second network 699 (e.g., a long-range wirelesscommunication network). The electronic device 601 may communicate withthe electronic device 604 via the server 608. The electronic device 601may include a processor 620, a memory 630, an input device 650, a soundoutput device 655, a display device 660, an audio module 670, a sensormodule 676, an interface 677, a haptic module 679, a camera module 680,a power management module 688, a battery 689, a communication module690, a subscriber identification module (SIM) 696, or an antenna module697. In one embodiment, at least one (e.g., the display device 660 orthe camera module 680) of the components may be omitted from theelectronic device 601, or one or more other components may be added tothe electronic device 601. In one embodiment, some of the components maybe implemented as a single integrated circuit (IC). For example, thesensor module 676 (e.g., a fingerprint sensor, an iris sensor, or anilluminance sensor) may be embedded in the display device 660 (e.g., adisplay).

The processor 620 may execute, for example, software (e.g., a program640) to control at least one other component (e.g., a hardware or asoftware component) of the electronic device 601 coupled with theprocessor 620, and may perform various data processing or computations.As at least part of the data processing or computations, the processor620 may load a command or data received from another component (e.g.,the sensor module 676 or the communication module 690) in volatilememory 632, process the command or the data stored in the volatilememory 632, and store resulting data in non-volatile memory 634. Theprocessor 620 may include a main processor 621 (e.g., a centralprocessing unit (CPU) or an application processor (AP)), and anauxiliary processor 623 (e.g., a graphics processing unit (GPU), animage signal processor (ISP), a sensor hub processor, or a communicationprocessor (CP)) that is operable independently from, or in conjunctionwith, the main processor 621. Additionally or alternatively, theauxiliary processor 623 may be adapted to consume less power than themain processor 621, or execute a particular function. The auxiliaryprocessor 623 may be implemented as being separate from, or a part of,the main processor 621.

The auxiliary processor 623 may control at least some of the functionsor states related to at least one component (e.g., the display device660, the sensor module 676, or the communication module 690) among thecomponents of the electronic device 601, instead of the main processor621 while the main processor 621 is in an inactive (e.g., sleep) state,or together with the main processor 621 while the main processor 621 isin an active state (e.g., executing an application). According to oneembodiment, the auxiliary processor 623 (e.g., an image signal processoror a communication processor) may be implemented as part of anothercomponent (e.g., the camera module 680 or the communication module 690)functionally related to the auxiliary processor 623.

The memory 630 may store various data used by at least one component(e.g., the processor 620 or the sensor module 676) of the electronicdevice 601. The various data may include, for example, software (e.g.,the program 640) and input data or output data for a command relatedthererto. The memory 630 may include the volatile memory 632 or thenon-volatile memory 634.

The program 640 may be stored in the memory 630 as software, and mayinclude, for example, an operating system (OS) 642, middleware 644, oran application 646.

The input device 650 may receive a command or data to be used by othercomponent (e.g., the processor 620) of the electronic device 601, fromthe outside (e.g., a user) of the electronic device 601. The inputdevice 650 may include, for example, a microphone, a mouse, or akeyboard.

The sound output device 655 may output sound signals to the outside ofthe electronic device 601. The sound output device 655 may include, forexample, a speaker or a receiver. The speaker may be used for generalpurposes, such as playing multimedia or recording, and the receiver maybe used for receiving an incoming call. According to one embodiment, thereceiver may be implemented as being separate from, or a part of, thespeaker.

The display device 660 may visually provide information to the outside(e.g., a user) of the electronic device 601. The display device 660 mayinclude, for example, a display, a hologram device, or a projector andcontrol circuitry to control a corresponding one of the display,hologram device, and projector. According to one embodiment, the displaydevice 660 may include touch circuitry adapted to detect a touch, orsensor circuitry (e.g., a pressure sensor) adapted to measure theintensity of force incurred by the touch.

The audio module 670 may convert a sound into an electrical signal andvice versa. According to one embodiment, the audio module 670 may obtainthe sound via the input device 650, or output the sound via the soundoutput device 655 or a headphone of an external electronic device 602directly (e.g., wiredly) or wirelessly coupled with the electronicdevice 601.

The sensor module 676 may detect an operational state (e.g., power ortemperature) of the electronic device 601 or an environmental state(e.g., a state of a user) external to the electronic device 601, andthen generate an electrical signal or data value corresponding to thedetected state. The sensor module 676 may include, for example, agesture sensor, a gyro sensor, an atmospheric pressure sensor, amagnetic sensor, an acceleration sensor, a grip sensor, a proximitysensor, a color sensor, an infrared (IR) sensor, a biometric sensor, atemperature sensor, a humidity sensor, or an illuminance sensor.

The interface 677 may support one or more specified protocols to be usedfor the electronic device 601 to be coupled with the external electronicdevice 602 directly (e.g., wiredly) or wirelessly. According to oneembodiment, the interface 677 may include, for example, a highdefinition multimedia interface (HDMI), a universal serial bus (USB)interface, a secure digital (SD) card interface, or an audio interface.

A connecting terminal 678 may include a connector via which theelectronic device 601 may be physically connected with the externalelectronic device 602. According to one embodiment, the connectingterminal 678 may include, for example, an HDMI connector, a USBconnector, an SD card connector, or an audio connector (e.g., aheadphone connector).

The haptic module 679 may convert an electrical signal into a mechanicalstimulus (e.g., a vibration or a movement) or an electrical stimuluswhich may be recognized by a user via tactile sensation or kinestheticsensation. According to one embodiment, the haptic module 679 mayinclude, for example, a motor, a piezoelectric element, or an electricalstimulator.

The camera module 680 may capture a still image or moving images.According to one embodiment, the camera module 680 may include one ormore lenses, image sensors, image signal processors, or flashes.

The power management module 688 may manage power supplied to theelectronic device 601. The power management module 688 may beimplemented as at least part of, for example, a power managementintegrated circuit (PMIC).

The battery 689 may supply power to at least one component of theelectronic device 601. According to one embodiment, the battery 689 mayinclude, for example, a primary cell which is not rechargeable, asecondary cell which is rechargeable, or a fuel cell.

The communication module 690 may support establishing a direct (e.g.,wired) communication channel or a wireless communication channel betweenthe electronic device 601 and the external electronic device (e.g., theelectronic device 602, the electronic device 604, or the server 608) andperforming communication via the established communication channel. Thecommunication module 690 may include one or more communicationprocessors that are operable independently from the processor 620 (e.g.,the AP) and supports a direct (e.g., wired) communication or a wirelesscommunication. According to one embodiment, the communication module 690may include a wireless communication module 692 (e.g., a cellularcommunication module, a short-range wireless communication module, or aglobal navigation satellite system (GNSS) communication module) or awired communication module 694 (e.g., a local area network (LAN)communication module or a power line communication (PLC) module). Acorresponding one of these communication modules may communicate withthe external electronic device via the first network 698 (e.g., ashort-range communication network, such as Bluetooth™, wireless-fidelity(Wi-Fi) direct, or a standard of the Infrared Data Association (IrDA))or the second network 699 (e.g., a long-range communication network,such as a cellular network, the Internet, or a computer network (e.g.,LAN or wide area network (WAN)). These various types of communicationmodules may be implemented as a single component (e.g., a single IC), ormay be implemented as multiple components (e.g., multiple ICs) that areseparate from each other. The wireless communication module 692 mayidentify and authenticate the electronic device 601 in a communicationnetwork, such as the first network 698 or the second network 699, usingsubscriber information (e.g., international mobile subscriber identity(IMSI)) stored in the subscriber identification module 696.

The antenna module 697 may transmit or receive a signal or power to orfrom the outside (e.g., the external electronic device) of theelectronic device 601. According to one embodiment, the antenna module697 may include one or more antennas, and, therefrom, at least oneantenna appropriate for a communication scheme used in the communicationnetwork, such as the first network 698 or the second network 699, may beselected, for example, by the communication module 690 (e.g., thewireless communication module 692). The signal or the power may then betransmitted or received between the communication module 690 and theexternal electronic device via the selected at least one antenna.

At least some of the above-described components may be mutually coupledand communicate signals (e.g., commands or data) therebetween via aninter-peripheral communication scheme (e.g., a bus, a general purposeinput and output (GPIO), a serial peripheral interface (SPI), or amobile industry processor interface (MIPI)).

According to one embodiment, commands or data may be transmitted orreceived between the electronic device 601 and the external electronicdevice 604 via the server 608 coupled with the second network 699. Eachof the electronic devices 602 and 604 may be a device of a same type as,or a different type, from the electronic device 601. All or some ofoperations to be executed at the electronic device 601 may be executedat one or more of the external electronic devices 602, 604, or 608. Forexample, if the electronic device 601 should perform a function or aservice automatically, or in response to a request from a user oranother device, the electronic device 601, instead of, or in additionto, executing the function or the service, may request the one or moreexternal electronic devices to perform at least part of the function orthe service. The one or more external electronic devices receiving therequest may perform the at least part of the function or the servicerequested, or an additional function or an additional service related tothe request, and transfer an outcome of the performing to the electronicdevice 601. The electronic device 601 may provide the outcome, with orwithout further processing of the outcome, as at least part of a replyto the request. To that end, a cloud computing, distributed computing,or client-server computing technology may be used, for example.

One embodiment may be implemented as software (e.g., the program 640)including one or more instructions that are stored in a storage medium(e.g., internal memory 636 or external memory 638) that is readable by amachine (e.g., the electronic device 601). For example, a processor ofthe electronic device 601 may invoke at least one of the one or moreinstructions stored in the storage medium, and execute it, with orwithout using one or more other components under the control of theprocessor. Thus, a machine may be operated to perform at least onefunction according to the at least one instruction invoked. The one ormore instructions may include code generated by a complier or codeexecutable by an interpreter. A machine-readable storage medium may beprovided in the form of a non-transitory storage medium. The term“non-transitory” indicates that the storage medium is a tangible device,and does not include a signal (e.g., an electromagnetic wave), but thisterm does not differentiate between where data is semi-permanentlystored in the storage medium and where the data is temporarily stored inthe storage medium.

According to one embodiment, a method of the disclosure may be includedand provided in a computer program product. The computer program productmay be traded as a product between a seller and a buyer. The computerprogram product may be distributed in the form of a machine-readablestorage medium (e.g., a compact disc read only memory (CD-ROM)), or bedistributed (e.g., downloaded or uploaded) online via an applicationstore (e.g., Play Store™), or between two user devices (e.g., smartphones) directly. If distributed online, at least part of the computerprogram product may be temporarily generated or at least temporarilystored in the machine-readable storage medium, such as memory of themanufacturer's server, a server of the application store, or a relayserver.

According to one embodiment, each component (e.g., a module or aprogram) of the above-described components may include a single entityor multiple entities. One or more of the above-described components maybe omitted, or one or more other components may be added. Alternativelyor additionally, a plurality of components (e.g., modules or programs)may be integrated into a single component. In this case, the integratedcomponent may still perform one or more functions of each of theplurality of components in the same or similar manner as they areperformed by a corresponding one of the plurality of components beforethe integration. Operations performed by the module, the program, oranother component may be carried out sequentially, in parallel,repeatedly, or heuristically, or one or more of the operations may beexecuted in a different order or omitted, or one or more otheroperations may be added.

Although certain embodiments of the present disclosure have beendescribed in the detailed description of the present disclosure, thepresent disclosure may be modified in various forms without departingfrom the scope of the present disclosure. Thus, the scope of the presentdisclosure shall not be determined merely based on the describedembodiments, but rather determined based on the accompanying claims andequivalents thereto.

1. A system for compensating in-phase (I) and quadrature (Q) mismatch(IQMM), comprising: an IQ mismatch compensator (IQMC) configured to:compensate for IQMM in a time domain, including frequency dependentIQMM, between a time-domain I signal and a time-domain Q signal usingfilter weight coefficients; and output a compensated I signal and acompensated Q signal; a fast Fourier transformation (FFT) circuitconfigured to perform an FFT on the compensated I signal and thecompensated Q signal to a frequency-domain compensated signal; and acoefficient updater configured to update the filter weight coefficientsbased on a frequency-domain observation of the frequency-domaincompensated signal.
 2. The system of claim 1, wherein the IQMC isfurther configured to receive the updated filter weight coefficientsfrom the coefficient updater and compensate for IQMM using the updatedfilter weight coefficients.
 3. The system of claim 1, wherein thecoefficient updater is further configured to determine the updatedfilter weight coefficients based on a gradient of a cost function of thefrequency-domain observation
 4. The system of claim 3, wherein thegradient of the frequency-domain cost function is a function of thefilter weight coefficients and the frequency-domain observation.
 5. Thesystem of claim 3, wherein the frequency-domain cost function is basedon kurtosis of the frequency-domain observation.
 6. The system of claim3, wherein the coefficient updater is configured to update the filterweight coefficients based on a gradient descent algorithm applying thegradient of the cost function.
 7. The system of claim 3, wherein thefrequency-domain cost function is based on a Euclidean distance betweenthe frequency-domain observation and a constellation, and wherein theconstellation is based on a known reference signal and channel response.8. A method for compensating in-phase (I) and quadrature (Q) mismatch(IQMM), comprising: compensating, with an IQ mismatch compensator(IQMC), for IQMM in a time domain, including frequency dependent IQMM,between a time-domain I signal and a time-domain Q signal using filterweight coefficients; outputting, with the IQMC, a compensated I signaland a compensated Q signal; transforming, with a fast Fouriertransformation (FFT) circuit, the compensated I signal and thecompensated Q signal to a frequency-domain compensated signal; andupdating, with a coefficient updater, the filter weight coefficientsbased on a frequency-domain observation of the frequency-domaincompensated signal.
 9. The method of claim 8, further comprising:receiving, with the IQMC, the updated filter weight coefficients fromthe coefficient updater; and compensating, with the IQMC, for IQMM usingthe updated filter weight coefficients.
 10. The method of claim 8,further comprising determining, with the coefficient updater, theupdated filter weight coefficients based on a gradient of a costfunction of the frequency-domain observation.
 11. The method of claim10, wherein the gradient of the frequency-domain cost function is afunction of the filter weight coefficients and the frequency-domainobservation.
 12. The method of claim 10, wherein the frequency-domaincost function is based on kurtosis of the frequency-domain observation.13. The method of claim 10, wherein the filter weight coefficients areupdated based on a gradient descent algorithm applying the gradient ofthe cost function.
 14. The method of claim 10, wherein thefrequency-domain cost function is based on a Euclidean distance betweenthe frequency-domain observation and a constellation, and wherein theconstellation is based on a known reference signal and channel response.15. An electronic device for compensating in-phase (I) and quadrature(Q) mismatch (IQMM), comprising: an IQ mismatch compensator (IQMC); acoefficient updater, a fast Fourier transformation (FFT) circuit; aprocessor; and a non-transitory computer readable storage medium storinginstructions that, when executed, cause the processor to: compensate,with the IQMC, for IQMM in a time domain, including frequency dependentIQMM, between a time-domain I signal and a time-domain Q signal usingfilter weight coefficients; output, with the IQMC, a compensated Isignal and a compensated Q signal; transform, with the FFT circuit, thecompensated I signal and the compensated Q signal to a frequency-domaincompensated signal; and update, with the coefficient updater, the filterweight coefficients based on a frequency-domain observation of thefrequency-domain compensated signal.
 16. The electronic device of claim15, wherein the instructions, when executed, further cause the processorto determine, with the coefficient updater, the updated filter weightcoefficients based on a gradient of a cost function of thefrequency-domain observation
 17. The electronic device of claim 16,wherein the gradient of the frequency-domain cost function is a functionof the filter weight coefficients and the frequency-domain observation.18. The electronic device of claim 16, wherein the frequency-domain costfunction is based on kurtosis of the frequency-domain observation. 19.The electronic device of claim 16, wherein the filter weightcoefficients are updated based on a gradient descent algorithm applyingthe gradient of the cost function.
 20. The electronic device of claim16, wherein the frequency-domain cost function is based on a Euclideandistance between the frequency-domain observation and a constellation,and wherein the constellation is based on a known reference signal andchannel response.